Rapid prototyping (RP) technologies such as layered manufacturing and other similar technologies enable the manufacture of complex three-dimensional (3D) parts. Rapid prototyping technologies, in particular, generally construct parts by building one layer at a time for use in, for example, the toy, automotive, aircraft and medical industries. Prototypes made by rapid prototyping technologies aid in research and development and provide a low cost alternative to traditional prototyping.
One method of RP technologies uses a chemical process called photopolymerization. Photopolymerization is primarily used in RP technologies to produce a solid part from a liquid. When building 3D objects using photopolymerization a vat of liquid photopolymer is placed under a digital light processing (DLP) projector or a laser scanner. The exposed liquid polymer hardens. The build plate then moves up or down in small increments and the liquid polymer is again exposed to light. The process repeats until the model has been built.
Stereolithography is one of the most widely used RP technologies used for producing models, prototypes, patterns, and production parts. Stereolithography, a 3D printing technology, employs a vat of liquid photopolymer resin and an ultraviolet laser to build parts' layers one at a time. For each layer, the laser beam traces a cross-section of the part pattern on the surface of the liquid resin. Exposure to the ultraviolet laser light cures and solidifies the pattern traced on the resin and joins it to the layer below.
In conventional stereolithography systems, a support plate is provided within a container filled with photopolymerizable or light-hardenable material, wherein a layer at the surface of the material is selectively irradiated, e.g. by means of a scanning laser beam, until a defined layer thickness is hardened. After hardening a layer, the support plate is lowered by the following layer thickness, and a new non-hardened material is applied.
The resolution of stereolithography machines and the ability of stereolithography to manufacture highly complex 3D objects, make stereolithography ideal for building both functional and non-functional prototypes.